Medical personnel in intensive care units or in A & E (Accident and Emergency) departments have come to rely more and more on mobile X-ray imagers. They afford acquisition of X-ray images even under awkward, adverse conditions. For example elderly patients in care homes who have been bed-ridden for long will need to have a chest X-ray taken every day to monitor for possible build-up of water in their lungs which could lead to pneumonia. It has been however noted that, although some of those mobile X-ray imagers are equipped with devices (such as collimators) to help keep dosage down, X-ray dosages for patients and personnel were still surprisingly high. A mobile X-ray imager is described in Applicant's WO2008/023301.
A particular problem in such apparatus is that it is difficult to determine an optimal setting for the collimator. Moreover, achieving a proper alignment of the X-ray source and the detector is cumbersome.